Controlled release of lidocaine as a model drug from polyurethane matrices will be investigated as a novel approach for the therapy of experimental ventricular tachycardia (VT) and prevention of ventricular fibrillation (VF). Ventricular tachyarrhythmias are a leading cause of morbidity and mortality. Current therapy has been only partially effective in the management of this problem, and virtually all of the anti-arrhythmic agents have significant adverse effects related in part to systemic administration. The objective of this proposal will be to investigate this unique approach to antiarrhythmic administration in dogs. It is hypothesized that controlled release of minimal but drug doses will produce high local concentration at the site where it is needed will be effective while avoiding adverse effects associated with systemic administration. The specific aims of the project are: 1) Formulate lidocaine- polyurethane controlled release matrices, with either a fixed or magnetically modulated release rate. 2) Investigate the effectiveness of controlled release lidocaine for experimental ventricular tachyarrhythmias in the dog. 3) Formulate a strategy for the computer controlled closed-loop feed-back modulation of site specific controlled release. The goal of this program will be to explore the advantages of controlled release for cardiac arrhythmias.